How can I prepare quantitative aptitude and DI LR for the CAT in 100 days? I will have to start from scratch. What are some books?

Yes you can do this for sure .People have done it with 2–3 months preparation. So here is the layout.Hope it helps-

First of all you need to know how strong your basics are as you might have had gap in between the studies of Mathematics ,English and Grammar ,so i would suggest you to solve few past CAT papers just to know where you stand .By the end of this practice you will know your strong and weak zones.

1.Make a note of your weak areas in a excel sheet .Mark them as red.Work more on those red areas if required start from scratch .Start from basics ,give sectional mock test and analyse what went right and what went wrong .And the reasoning behind all your answer.This is the area you should prepare throughly say for 3-4 month depending upon the number of topic you have marked as red.Topic like RC,DI,LR have more weightage in CAT so requires your maximum attention .If you are weak in say Permutation and Combination ,probability .You can afford to spent little less time on such topic .As maximum3-4 question comes from them . In most cases 1–2 .You are better off doing a topic like RC, Critical reasoning than a phrasal verb.

2. Now coming to your medium and strong areas just go through the basics once and daily solve like 5-10 problems from them to keep in touch till D- day comes.

3. Also read the newspaper editorial daily. Read the subject you are not really comfortable with.You can refer Hindu editorial and read articles at www.aldaily.com

4.Also as far as classes is concerned i will suggest you to look for Handa ka Funda .The tips and techniques are really useful .You would like to go through the link -Online Coaching for CAT and Banking Exams. Also GK course of Handa ka Funda will help you prepare for exam apart from CAT like XAT ,SNAP,IIFT,TISS.You can get tips and tricks needed for mocks from the course.You can get reviews about course here-What is your review of Handa Ka Funda?. But if you have joined the TIME or any other institute you can go ahead with it .

5. As far as mocks are concerned i would suggest you join CL Mocks as they are at par with CAT and AIMCATS,SIMCATS are generally way above CAT level.

6.Analyse the mocks which is more important than giving a mock .Do not attempt another mock without analysis one mock .Start taking mocks from the month of August last week .

7. 1-1.5 months before actual Cat give 2 mocks per week and here again analyse the mock .

8. Just an week before actual cat exam ,stop attempting cat mock test .Try to solve past cat exam paper with 70–80% accuracy.

The important thing Stay positive ,Stay Calm.Strange things have happened in CAT people who work hard are definitely rewarded in CAT .